1.0 TENSION
1.4 Side Face Blowout Failure Mode
Results ϕ nonductile
Results ACI 318-19 Chapter 17 Provision Comments for PROFIS Engineering
ϕ nonductile
ACI 318-19 Section 17.10.5.4 17.10.5.4 The anchor design tensile strength shall be calculated from ( a ) through ( e ) for the failure modes given in Table 17.5.2 assuming the concrete is cracked unless it can be demonstrated that the concrete remains uncracked :
( a ) ϕN sa for a single anchor or for the most highly stressed individual anchor in an anchor group
[ ϕN sa corresponds to steel failure ( tension ) in Table 17.5.2 ] ( b ) 0.75ϕN cb or 0.75ϕN cbg except that N cb or N cbg need not be calculated if anchor reinforcement satisfying 17.5.2.1 ( a ) is provided
[ ϕN cb or ϕN cbg correspond to concrete breakout failure ( tension ) in Table 17.5.2 ]
( c ) 0.75ϕN pn for a single anchor or for the most highly stressed individual anchor in an anchor group
[ ϕN pn corresponds to pullout failure ( tension ) in Table 17.5.2 ] ( d ) 0.75ϕN sb or 0.75ϕN sbg
[ ϕN sb or ϕN sbg correspond to side-face blowout failure ( tension ) in Table 17.5.2 ]
( e ) 0.75ϕN a or 0.75ϕN ag
[ ϕN a or ϕN ag correspond to bond failure ( tension ) in Table 17.5.2 ] where ϕ is in accordance with 17.5.3 .
ACI 318-08 Part D . 3.3.6 D . 3.3.6 — As an alternative to D . 3.3.4 and D . 3.3.5 , it shall be permitted to take the design strength of the anchors as 0.4 times the design strength determined in accordance with D . 3.3.3 . For the anchors of stud bearing walls , it shall be permitted to take the design strength of the anchors as 0.5 times the design strength determined in accordance with D . 3.3.3 .
ACI 318-19 strength design provisions for side-face blowout failure in tension require calculation of a nominal side-face blowout strength ( N sb or N sbg
). The nominal strength is multiplied by one or more strength reduction factors ( ϕ-factors ) to obtain a design side-face blowout strength ( ϕN sb or ϕN sbg
). ϕ-factors are relevant to static and seismic load conditions .
PROFIS Engineering designates the 0.75 reduction factor noted in ACI 318-19 Section 17.10.5.4 for seismic load conditions “ ϕ seismic
”. This reduction is applied to non-steel failure modes when calculating tension design strengths for both cast-in-place and post-installed anchors using ACI 318-19 anchoring-to-concrete provisions .
When using ACI 318-19 anchoring-to-concrete provisions to calculate the design side-face blowout strength in tension for cast-in-place anchors , the parameter “ ϕ concrete
” in the PROFIS Engineering report corresponds to the parameter “ ϕ ” shown in ACI 318-19 Table 17.5.3 ( b ).
The parameter “ ϕ nonductile
” is a reduction factor for seismic load conditions that is given in Part D . 3.3.6 of the anchoring-to-concrete provisions in ACI 318-08 Appendix D . This reduction factor can range from a value of 0.4 to 1.0 , depending on the application , and PROFIS Engineering designates this factor “ ϕ nonductile
”.
“ ϕ nonductile
” is not a relevant parameter for seismic design per ACI 318-19 Chapter 17 ; therefore , it is always referenced in the PROFIS Engineering report for ACI 318- 19 calculations as equal to 1.0 .
Reference the PROFIS Engineering Design Guide for ACI 318-08 anchoring-toconcrete provisions for more information on ϕ nonductile
.
132 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-19 Provisions